There is no struct task_task at all, thus it is a typo error in the old
commits, now fix it to what it should be in order to avoid unnecessary
misunderstanding.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427809596-29559-2-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Currently the perf kmem does not respect -i option.

Initializing the file.path properly after options get parsed.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1428298576-9785-2-git-send-email-namhyung@kernel.orgSigned-off-by: NNamhyung Kim <namhyung@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Currently it ignores operator priority and just sets processed args as a
right operand.  But it could result in priority inversion in case that
the right operand is also a operator arg and its priority is lower.

For example, following print format is from new kmem events.

  "page=%p", REC->pfn != -1UL ? (((struct page *)(0xffffea0000000000UL)) + (REC->pfn)) : ((void *)0)

But this was treated as below:

  REC->pfn != ((null - 1UL) ? ((struct page *)0xffffea0000000000UL + REC->pfn) : (void *) 0)

In this case, the right arg was '?' operator which has lower priority.
But it just sets the whole arg so making the output confusing - page was
always 0 or 1 since that's the result of logical operation.

With this patch, it can handle it properly like following:

  ((REC->pfn != (null - 1UL)) ? ((struct page *)0xffffea0000000000UL + REC->pfn) : (void *) 0)
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1428298576-9785-10-git-send-email-namhyung@kernel.org
[ Replaced 'swap' with 'rotate' in a comment as requested by Steve and agreed by Namhyung ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

This patch add checks in places where map__kmap is used to get kmaps
from struct kmap.

Error messages are added at map__kmap to warn invalid accessing of kmap
(for the case of !map->dso->kernel, kmap(map) does not exists at all).

Also, introduces map__kmaps() to warn uninitialized kmaps.
Reviewed-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Cc: pi3orama@163.com
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1428394966-131044-2-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

perf_evlist__mmap_consume() uses perf_mmap__empty() to judge whether
perf_mmap is empty and can be released. But the result is inverted so
fix it.
Signed-off-by: NHe Kuang <hekuang@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1428399071-7141-1-git-send-email-hekuang@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf data convert to use perf.data when it is not owned by
current user or root.

Example:

 # perf record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 28260 Apr  2 17:35 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf data convert --to-ctf=./ctf-data/
 File perf.data not owned by current user or root (use -f to override)
 # perf data convert --to-ctf=./ctf-data/ -f
   Error: unknown switch `f'

  usage: perf data convert [<options>]

     -v, --verbose         be more verbose
     -i, --input <file>    input file name
         --to-ctf ...      Convert to CTF format

After this patch:

 # perf data convert --to-ctf=./ctf-data/
 File perf.data not owned by current user or root (use -f to override)
 # perf data convert --to-ctf=./ctf-data/ -f
 # ls ctf-data/
 metadata  perf_stream_0

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-11-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf trace to use perf.data when it is not owned by current user
or root.

Example:

 # perf trace record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 4153101 Apr  2 15:28 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf trace -i perf.data
 File perf.data not owned by current user or root (use -f to override)
 # perf trace -i perf.data -f
   Error: unknown switch `f'

  usage: perf trace [<options>] [<command>]
     or: perf trace [<options>] -- <command> [<options>]
     or: perf trace record [<options>] [<command>]
     or: perf trace record [<options>] -- <command> [<options>]

         --event <event>   event selector. use 'perf list' to list
 						  available events
         --comm            show the thread COMM next to its id
         --tool_stats      show tool stats
     -e, --expr <expr>     list of events to trace
     -o, --output <file>   output file name
     -i, --input <file>    Analyze events in file
     -p, --pid <pid>       trace events on existing process id
     -t, --tid <tid>       trace events on existing thread id
         --filter-pids <float>
  ...

As shown above, the -f option does not work at all.

After this patch:

 # perf trace -i perf.data
 File perf.data not owned by current user or root (use -f to override)
 # perf trace -i perf.data -f
 0.056 ( 0.002 ms): ls/47325 brk(                                 ...
 0.108 ( 0.018 ms): ls/47325 mmap(len: 4096, prot: READ|WRITE,    ...
 0.145 ( 0.013 ms): ls/47325 access(filename: 0x7f31259a0eb0,     ...
 0.172 ( 0.008 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.180 ( 0.004 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.185 ( 0.004 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.189 ( 0.003 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.195 ( 0.004 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.199 ( 0.002 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.205 ( 0.004 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.211 ( 0.004 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.220 ( 0.007 ms): ls/47325 open(filename: 0x7f312599e8ff,       ...
 ...
 ...

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-10-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf timechart to use perf.data when it is not owned by current
user or root.

Example:

 # perf timechart record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 5471744 Apr  2 15:15 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf timechart
 File perf.data not owned by current user or root (use -f to override)
 # perf timechart -f
   Error: unknown switch `f'

  usage: perf timechart [<options>] {record}

     -i, --input <file>    input file name
     -o, --output <file>   output file name
     -w, --width <n>       page width
         --highlight <duration or task name>
                           highlight tasks. Pass duration in ns or process name.
     -P, --power-only      output power data only
     -T, --tasks-only      output processes data only
     -p, --process <process>
                           process selector. Pass a pid or process name.
         --symfs <directory>
                           Look for files with symbols relative to this directory
     -n, --proc-num <n>    min. number of tasks to print
     -t, --topology        sort CPUs according to topology
         --io-skip-eagain  skip EAGAIN errors
         --io-min-time <time>
                           all IO faster than min-time will visually appear longer
         --io-merge-dist <time>
                           merge events that are merge-dist us apart

As shown above, the -f option does not work at all.

After this patch:

 # perf timechart
 File perf.data not owned by current user or root (use -f to override)
 # perf timechart -f
 Written 0.0 seconds of trace to output.svg.
 # cat output.svg
 <?xml version="1.0" standalone="no"?>
 <!DOCTYPE svg SYSTEM "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
 <svg width="1000" height="10110" version="1.1" xmlns="http://www.w3.org/2000/svg">
 <defs>
   <style type="text/css">
     <![CDATA[
       rect          { stroke-width: 1; }
 ...
 ...

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-9-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf script to use perf.data when it is not owned by current user
or root. Change the short option name of --fields to -F to avoid confusion
with --force.

Example:

 # perf record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 28360 Apr  2 14:53 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf script
 File perf.data not owned by current user or root (use -f to override)
 # perf script -f
   Error: switch `f' requires a value

  usage: perf script [<options>]
     or: perf script [<options>] record <script> [<record-options>] <command>
     or: perf script [<options>] report <script> [script-args]
     or: perf script [<options>] <script> [<record-options>] <command>
     or: perf script [<options>] <top-script> [script-args]

     -f, --fields <str>    comma separated output fields prepend with
     'type:'. Valid types: hw,sw,trace,raw. Fields:
     comm,tid,pid,time,cpu,event,trace,ip,sym,dso,addr,symoff,period

As shown above, the -f option does not work at all. And -f is already
taken up by --fields, which makes --force confused, so change the short
option name of --fields to -F like what other perf commands do (e.g.
perf report -F) and use -f as the short option name of --force.

After this patch:

 # perf script
 File perf.data not owned by current user or root (use -f to override)
 # perf script -f
 :41298 41298 2590086.564226:          1 cycles:  ffffffff8103efc6
 native_write_msr_safe ([kernel.kallsyms])
 :41298 41298 2590086.564244:          1 cycles:  ffffffff8103efc6
 native_write_msr_safe ([kernel.kallsyms])
 :41298 41298 2590086.564249:          7 cycles:  ffffffff8103efc6
 native_write_msr_safe ([kernel.kallsyms])
 :41298 41298 2590086.564255:        176 cycles:  ffffffff8103efc6
 native_write_msr_safe ([kernel.kallsyms])
     ls 41298 2590086.567346:       4059 cycles:  ffffffff8105a592
     raise_softirq ([kernel.kallsyms])
     ls 41298 2590086.567353:       3717 cycles:  ffffffff8105a592
     raise_softirq ([kernel.kallsyms])
     ls 41298 2590086.567358:      63058 cycles:  ffffffff8105a592
     raise_softirq ([kernel.kallsyms])
     ls 41298 2590086.567448:    1706255 cycles:            406ae0
     [unknown] (/usr/bin/ls)

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-8-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf mem to use perf.data when it is not owned by current user or
root.

Example:

 # perf mem -t load record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 16392 Apr  2 14:34 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf mem -D report
 File perf.data not owned by current user or root (use -f to override)
 # perf mem -D -f report
   Error: unknown switch `f'

  usage: perf mem [<options>] {record|report}

     -t, --type <type>     memory operations(load,store) Default load,store
     -D, --dump-raw-samples
                           dump raw samples in ASCII
     -U, --hide-unresolved
                           Only display entries resolved to a symbol
     -i, --input <file>    input file name
     -C, --cpu <cpu>       list of cpus to profile
     -x, --field-separator <separator>
                           separator for columns, no spaces will be added
                           between columns '.' is reserved.

As shown above, the -f option does not work at all.

After this patch:

 # perf mem -D report
 File perf.data not owned by current user or root (use -f to override)
 # perf mem -D -f report
 # PID, TID, IP, ADDR, LOCAL WEIGHT, DSRC, SYMBOL
 39095 39095 0xffffffff81127e40 0x016ffff887f45148338 8 0x68100142
 /proc/kcore:perf_event_aux
 39095 39095 0xffffffff8100a3fe 0xffff89007f8cb7d0 6 0x68100142
 /proc/kcore:native_sched_clock
 39095 39095 0xffffffff81309139 0xffff88bf44c9ded8 6 0x68100142
 /proc/kcore:acpi_map_lookup
 39095 39095 0xffffffff810f8c4c 0xffff89007f8ccd88 6 0x68100142
 /proc/kcore:rcu_nmi_exit
 39095 39095 0xffffffff81136346 0xffff88fea995dd50 6 0x68100142
 /proc/kcore:unlock_page
 39095 39095 0xffffffff812a64a2 0xffff88fea995dcc8 6 0x68100142
 /proc/kcore:half_md4_transform
 39095 39095 0x7f0cf877c7e9 0x25dfb94 6 0x68100142
 /lib64/libc-2.19.so:__readdir64
 39095 39095 0x7f0cf87575a3 0x7f0cf9163731 6 0x68100142
 /lib64/libc-2.19.so:__strcoll_l
 39095 39095 0xffffffff8116910e 0xffffea01c1bfbd50 23 0x68100242
 /proc/kcore:page_remove_rmap

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-7-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf lock to use perf.data when it is not owned by current user
or root.

Example:

 # perf lock record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 4880686 Apr  2 14:14 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf lock report
 File perf.data not owned by current user or root (use -f to override)
 Initializing perf session failed
 # perf lock report -f
   Error: unknown switch `f'

  usage: perf lock report [<options>]

     -k, --key <acquired>  key for sorting (acquired / contended /
     avg_wait / wait_total / wait_max / wait_min)

As shown above, the -f option does not work at all.

After this patch:

 # perf lock report
 File perf.data not owned by current user or root (use -f to override)
 Initializing perf session failed
 # perf lock report -f
                Name   acquired  contended   avg wait (ns) total wait (ns) ...

 &ldata->output_l...        128          0               0               0 ...
          &ctx->lock        114          0               0               0 ...
         &p->pi_lock        112          0               0               0 ...
 &(&pool->lock)->...        112          0               0               0 ...
 &(&dentry->d_loc...         70          0               0               0 ...
 &(&newf->file_lo...         62          0               0               0 ...
 &(&fs->lock)->rl...         43          0               0               0 ...
 ...

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-6-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf kvm to use perf.data.guest when it is not owned by current
user or root.

Example:

 # perf kvm stat record ls
 # chown Yunlong.Song:Yunlong.Song perf.data.guest
 # ls -al perf.data.guest
 -rw------- 1 Yunlong.Song Yunlong.Song 4128937 Apr  2 11:05 perf.data.guest
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf kvm stat report
 File perf.data.guest not owned by current user or root (use -f to override)
 Initializing perf session failed
 # perf kvm stat report -f
   Error: unknown switch `f'

  usage: perf kvm stat report [<options>]

         --event <report event>
                           event for reporting: vmexit, mmio (x86 only),
                           ioport (x86 only)
         --vcpu <n>        vcpu id to report
     -k, --key <sort-key>  key for sorting: sample(sort by samples
 						   number) time (sort by avg time)
     -p, --pid <pid>       analyze events only for given process id(s)

As shown above, the -f option does not work at all.

After this patch:

 # perf kvm stat report
 File perf.data.guest not owned by current user or root (use -f to override)
 Initializing perf session failed
 # perf kvm stat report -f
 Analyze events for all VMs, all VCPUs:

   VM-EXIT    Samples  Samples%     Time%    Min Time    Max Time   Avg time

 Total Samples:0, Total events handled time:0.00us.

As shown above, the -f option really works now. Since we have not
launched any KVM related process, the result shows 0 sample here.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-5-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf kmem to use perf.data when it is not owned by current user
or root.

Example:

 # perf kmem record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 5315665 Apr  2 10:54 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf kmem stat
 File perf.data not owned by current user or root (use -f to override)
 # perf kmem stat -f
   Error: unknown switch `f'

  usage: perf kmem [<options>] {record|stat}

     -i, --input <file>    input file name
     -v, --verbose         be more verbose (show symbol address, etc)
         --caller          show per-callsite statistics
         --alloc           show per-allocation statistics
     -s, --sort <key[,key2...]>
                           sort by keys: ptr, call_site, bytes, hit,
                           pingpong, frag
     -l, --line <num>      show n lines
         --raw-ip          show raw ip instead of symbol

As shown above, the -f option does not work at all.

After this patch:

 # perf kmem stat
 File perf.data not owned by current user or root (use -f to override)
 # perf kmem stat -f
 SUMMARY
 =======
 Total bytes requested: 437599
 Total bytes allocated: 615472
 Total bytes wasted on internal fragmentation: 177873
 Internal fragmentation: 28.900259%
 Cross CPU allocations: 6/1192

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-4-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf inject to use perf.data when it is not owned by current user
or root.

Example:

 # perf record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 28260 Apr  2 10:37 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf inject -v -b -i perf.data -o perf.data.new
 File perf.data not owned by current user or root (use -f to override)
 # perf inject -v -b -i perf.data -o perf.data.new -f
   Error: unknown switch `f'

  usage: perf inject [<options>]

     -b, --build-ids       Inject build-ids into the output stream
     -i, --input <file>    input file name
     -o, --output <file>   output file name
     -s, --sched-stat      Merge sched-stat and sched-switch for getting
     events where and how long tasks slept
     -v, --verbose         be more verbose (show build ids, etc)
         --kallsyms <file>
                           kallsyms pathname

As shown above, the -f option does not work at all.

After this patch:

 # perf inject -v -b -i perf.data -o perf.data.new
 File perf.data not owned by current user or root (use -f to override)
 # perf inject -v -b -i perf.data -o perf.data.new -f
 build id event received for [kernel.kallsyms]:
 f6dcb66d8b98f1c0d9eb87bf043444b69f91d30c
 symsrc__init: cannot get elf header.
 Looking at the vmlinux_path (7 entries long)
 Using /proc/kcore for kernel object code
 Using /proc/kallsyms for symbols

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-3-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf evlist to use perf.data when it is not owned by current user
or root.

Example:

 # perf record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 28260 Apr  2 10:18 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf evlist
 File perf.data not owned by current user or root (use -f to override)
 # perf evlist -f
   Error: unknown switch `f'

  usage: perf evlist [<options>]

     -i, --input <file>    Input file name
     -F, --freq            Show the sample frequency
     -v, --verbose         Show all event attr details
     -g, --group           Show event group information

As shown above, the -f option does not work at all.

After this patch:

 # perf evlist
 File perf.data not owned by current user or root (use -f to override)
 # perf evlist -f
 cycles

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-2-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Fix 'perf probe' to track down unnamed union/structure members.

perf probe did not track down the tree of unnamed union/structure
members, since it just failed to find given "name" in a parent
structure/union.  To solve this issue, I've introduced 2 changes.

- Fix die_find_member() to track down the type-DIE if it is
  unnamed, and if it contains the specified member, returns the
  unnamed member.
  (note that we don't return found member, since unnamed member
   has the offset in the parent structure)
- Fix convert_variable_fields() to track down the unnamed union/
  structure (one-by-one).

With this patch, perf probe can access unnamed fields:
  -----
  #./perf probe -nfx ./perf lock__delete ops 'locked_ops=ops->locked.ops'
  Added new event:
    probe_perf:lock__delete (on lock__delete in /home/mhiramat/ksrc/linux-3/tools/perf/perf with ops locked_ops=ops->locked.ops)

  You can now use it in all perf tools, such as:

          perf record -e probe_perf:lock__delete -aR sleep 1
  -----
Reported-by: NArnaldo Carvalho de Melo <acme@kernel.org>
Report-Link: https://lkml.org/lkml/2015/3/5/431Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150402073312.14482.37942.stgit@localhost.localdomainSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

As it comes from address_location->thread, that is already stored as
export_sample->al, where the thread can be obtained.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20150402141542.GA9630@kernel.org
Link: http://lkml.kernel.org/n/tip-bzotbl4epoztw0jd6sm2stpf@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

As it is available via another parameter, address_location->thread.
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: lkml.kernel.org/r/551D08F8.3040706@intel.com
Link: http://lkml.kernel.org/n/tip-6dbn0tcm9hyv92g7h3zj2dbt@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

It is already in the addr_location, so remove the redundant 'thread'
parameter from the callback signatures.
Acked-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1427906210-10519-3-git-send-email-acme@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

We get the thread when we call perf_event__preprocess_sample(), no need
to do it before that.
Acked-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1427906210-10519-2-git-send-email-acme@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

As these can be obtained from the ordered_events pointer, via
container_of, reducing the cross section of ordered_samples.

These were added to ordered_samples in:

 commit b7b61cbe
 Author: Arnaldo Carvalho de Melo <acme@redhat.com>
 Date:   Tue Mar 3 11:58:45 2015 -0300

    perf ordered_events: Shorten function signatures

    By keeping pointers to machines, evlist and tool in ordered_events.

But that was more a transitional patch while moving stuff out from
perf_session.c to ordered_events.c and possibly not even needed by then,
as we could use the container_of() method and instead of having the
nr_unordered_samples stats in events_stats, we can have it in
ordered_samples.
Based-on-a-patch-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-4lk0t9js82g0tfc0x1onpkjt@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Even when it is not used to actually reorder events, some of its fields
are used, like session->ordered_events->tool, to shorten function
signatures where tool, for instance, was being passed, as the tool is
needed for the ordered_events code, we need it there and might as well
use it for other perf_session needs.

This fixes a problem where 'perf script' had some condition that made
session->ordered_events not to be initialized even with its
script->tool ordered_events related flags asking for it to be, which
looks like another bug and needs to be investigated further.

Always initializing session->ordered_events at least leaves the current
assumptions in place, so do it now.
Reported-by: NDavid Ahern <dsahern@gmail.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Tested-by: NDavid Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-b1xxk0rwkz2a0gip1uufmjqg@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

363b785f added synthesized fork events and set a thread's parent id to
itself. Since we are already processing /proc/<pid>/status the ppid can
be determined properly. Make it so.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Acked-by: NDon Zickus <dzickus@redhat.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Joe Mario <jmario@redhat.com>
Link: http://lkml.kernel.org/r/1427747758-18510-2-git-send-email-dsahern@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Rather than parsing /proc/pid/status file one line at a time, read it
into a buffer in one shot and search for all strings in one pass.

tgid conversion also simplified -- removing the isspace walk. As noted
by Arnaldo those are not needed for atoi == strtol calls.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Acked-by: NDon Zickus <dzickus@redhat.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Joe Mario <jmario@redhat.com>
Link: http://lkml.kernel.org/r/1427747758-18510-1-git-send-email-dsahern@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Commit 2e77784b ("perf callchain: Move cpumode resolve code to
add_callchain_ip") promised "No change in behavior.".

As this commit breaks callchains on s390x (symbols not getting resolved,
observed when profiling the kernel), this statement is wrong. The cpumode
must be kept when iterating over all ips, otherwise the default
(PERF_RECORD_MISC_USER) will be used by error.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1427703060-59883-1-git-send-email-dahi@linux.vnet.ibm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Disabling libbabeltrace check by default and replacing the
NO_LIBBABELTRACE make variable with LIBBABELTRACE.

Users wanting the libbabeltrace feature need to build via:

  $ make LIBBABELTRACE=1

The reason for this is that the libababeltrace interface we use (version
1.3) hasn't been packaged/released yet, thus the failing feature check
only slows down build and confuses other (non CTF) developers.
Requested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeremie Galarneau <jgalar@efficios.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20150328103030.GA8431@krava.redhat.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Guilherme Cox found that:

 There is, however, a potential bug if there is an item with code zero
 that is not the first one in the symbol list, since eval_flag(..)
 returns 0 when it doesn't find anything.

That is, if you have the following enums:

enum {
  FOO_START = 0,
  FOO_GO    = 1,
  FOO_END   = 2
}

and then have:

  __print_symbolic(foo, FOO_GO, "go", FOO_START, "start",
		        FOO_END, "end")

If none of the enums are known to pevent, then eval_flag() will return
zero, and it will match it to the first item in the list, which would be
FOO_GO, which is not zero.

Luckily, in most cases, the first element would be zero, and the parsing
would match out of sheer luck.
Reported-by: NGuilherme Cox <cox@computer.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20150324145813.0bfe95ba@gandalf.local.homeSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

 commit e596663e
 Author: Arnaldo Carvalho de Melo <acme@redhat.com>
 Date:   Fri Feb 13 13:22:21 2015 -0300

    perf trace: Handle multiple threads better wrt syscalls being intermixed

Introduced a bug where it considered the number of bytes output directly
to the output file when formatting the syscall entry buffer that is
stored to be finally printed at syscall exit, ending up leaving garbage
at the start of syscalls that appeared while another syscall was being
processed, in another thread. Fix it.

Example of garbage in the output before this patch:

 4280.102 (  0.000 ms): lsmd/763  ... [continued]: select()) = 0 Timeout
 4280.107 (275.250 ms): tuned/852 select(tvp: 0x7f41f7ffde50        ) ...
 4280.109 (  0.002 ms): lsmd/763 Xl��                                ) = -10
 4639.197 (  0.000 ms): systemd-journa/542  ... [continued]: epoll_wait()) = 1
 4639.202 (359.088 ms): lsmd/763 select(n: 6, inp: 0x7ffff21daad0, tvp: 0x7ffff21daac0) ...
 4639.207 (  0.005 ms): systemd-journa/542 Hn��                      ) = 106
 4639.221 (  0.002 ms): systemd-journa/542 uname(name: 0x7ffdbaed8e00) = 0
 4639.271 (  0.008 ms): systemd-journa/542 ftruncate(fd: 11</run/log/journal/60cd52417cf440a4a80107518bbd3c20/system.journal>, length: 50331648) = 0

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-9ckfe8mvsedgkg6y80gz1ul8@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Number of JOBS to use is set automatically to the number of processors found
in /proc/cpuinfo. SPARC uses 'CPU' lines rather than 'processor'. Update the
check in perf's Makefile to work for SPARC.
Signed-off-by: NDavid Ahern <david.ahern@oracle.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1427213455-127249-1-git-send-email-david.ahern@oracle.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

SPARC based systems currently support up to 1024 cpus (e.g. T5-8).
Allow perf to work on those systems.
Signed-off-by: NDavid Ahern <david.ahern@oracle.com>
Link: http://lkml.kernel.org/r/1427213438-127216-1-git-send-email-david.ahern@oracle.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Use of a bad filter currently generates the message:
 Error: failed to set filter with 22 (Invalid argument)

Add the event name to make it clear to which event the filter
failed to apply:
  Error: Failed to set filter "foo" on event sched:sg_lb_stats: 22: Invalid argument

To test it use something like:

 # perf record -e sched:sched_switch -e sched:*fork --filter parent_pid==1 -e sched:*wait* --filter bla usleep 1
  Error: failed to set filter "bla" on event sched:sched_stat_iowait with 22 (Invalid argument)
 #
Based-on-a-patch-by: NDavid Ahern <dsahern@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-d7gq2fjvaecozp9o2i0siifu@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

perf timechart -T on sparc64 is terminating due to SIGBUS. Backtrace:

Program received signal SIGBUS, Bus error.
0x0000000000173d7c in perf_evsel__intval (evsel=<value optimized out>, sample=0x7feffffda28, name=0x289b28 "prev_state")
    at util/evsel.c:1918
1918	util/evsel.c: No such file or directory.
	in util/evsel.c
Missing separate debuginfos, use: debuginfo-install audit-libs-2.3.7-1.0.1.el6.sparc64 bzip2-libs-1.0.5-7.el6_0.sparc64 elfutils-libelf-0.155-2.0.3.el6.sparc64 elfutils-libs-0.155-2.0.3.el6.sparc64 glibc-2.12-1.132.0.8.el6_5.sparc64 numactl-2.0.7-8.el6.sparc64 python-libs-2.6.6-52.0.2.el6.sparc64 slang-2.2.1-1.el6.sparc64 xz-libs-4.999.9-0.3.beta.20091007git.el6.sparc64 zlib-1.2.3-29.el6.sparc64
(gdb) bt
0  0x0000000000173d7c in perf_evsel__intval (evsel=<value optimized out>, sample=0x7feffffda28,
    name=0x289b28 "prev_state") at util/evsel.c:1918
1  0x0000000000123b94 in process_sample_sched_switch (tchart=0x7feffffe040, evsel=0x4ca850, sample=0x7feffffda28,
    backtrace=0xc39010 "") at builtin-timechart.c:627
2  0x0000000000122828 in process_sample_event (tool=0x7feffffe040, event=<value optimized out>, sample=0x7feffffda28,
    evsel=0x4ca850, machine=0x4c9c88) at builtin-timechart.c:569

Another extended load on unaligned pointer. As before fix by copying to
a temporary variable using memcpy.
Signed-off-by: NDavid Ahern <david.ahern@oracle.com>
Link: http://lkml.kernel.org/r/1427228049-51893-1-git-send-email-david.ahern@oracle.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The 'record' and 'top' tools already allow a user to specify a CSV of
pids and/or tids of tasks to collect data.

Add those options to the 'report' and 'script' analysis commands to only
consider samples related to the given pids/tids.

This is also inline with the existing comm option.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1427212361-7066-1-git-send-email-dsahern@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Required for off-box analysis to convert kernel addresses.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1427212317-7018-1-git-send-email-dsahern@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Since 6ea22486 ("tracing: Add array printing helper") trace can
generate traces with variable element size arrays.  Add support to
parse them.
Signed-off-by: NJavi Merino <javi.merino@arm.com>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1427195239-15730-1-git-send-email-javi.merino@arm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

valgrind showed that the filter token wasn't being freed properly in
process_filter().
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20150324135923.817723903@goodmis.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

For debugging purposes, it may be helpful for the kbuffer library to flag
when crossing a sub buffer.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20150324135923.650983637@goodmis.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

When a event PADDING is hit (a deleted event that is still in the ring
buffer), translate_data() sets the length of the padding and also updates
the data pointer which is passed back to the caller.

This is unneeded because the caller also updates the data pointer with
the passed back length. translate_data() should not update the pointer,
only set the length.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org # 3.12+
Link: http://lkml.kernel.org/r/20150324135923.461431960@goodmis.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

When a plugin option is defined, by default it is a boolean (true or false).

If the option is something else, then it needs to set its "value" field to
a default string other than NULL (can be just "").

If the value is not set then the option is considered boolean, and the
updating of the option value will be handled accordingly.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20150324135923.308372986@goodmis.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

There is a pevent_data_comm_from_pid() that returns the cmdline stored for
a given pid in order for users to map pids to comms, but there's no method
to convert a comm back to a pid. This is useful for filters that specify
a comm instead of a PID (it's faster than searching each individual event).

Add a way to retrieve a comm from a pid. Since there can be more than one
pid associated to a comm, it returns a data structure that lets the user
iterate over all the saved comms for a given pid.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20150324135923.001103479@goodmis.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>